killing Ich is a time consuming issue. It is a huge pain in the ass. Having a UV steralizer will keep outbreaks from happening. It is your best bet to keep things healthy in your tank as far as not having parasites.
To really get rid of it, you have to treat your fish with hyposalinity - which is keeping your fish in a salinity of 1.018-.019. over a period of 6 weeks to make sure the eggs and adult parasites are really dead. You would need to remove the fish from your tank and place them in a QT tank with a much lower salinity - .019 and leave alone your display tank for 6 weeks. that will insure all the nasty eggs are dead in your display tank as well (don't drop the display tank salinity). after 6 weeks of hyposalinity in your QT tank, return your now healthy fish to your display tank. Of course, if you introduce a new fish who has larvae on it you will have to do it all over again. Hence the importance of QT before putting fish in your display tank.
The other way is to cross your fingers and hope that by having a UV on your display tank that your fish can avoid getting infected after the first batch of Ich is dead and that larvae don't attach themselves to your fish. My fish had gotten it once and then never again. Some have survived, others not. Up to the healthy of the animal. Nasty stuff. Get a UV on your tank.
-Dr Marco :sfish: